VALUE CHAIN #
Carrot Value Chain
Harvest, handling, and storage
Carrots for processing are harvested between August 15 into late fall. The prime processing harvest period is between September 15 and October 25. Early fresh market carrots are harvested from late July to September and late carrots are harvested into October. For the wholesale fresh market, carrots must be over 5 inches long and between 3/4 and 1 1/2 inches in diameter. Carrots harvested and handled in hot weather are more likely to decay, and care should be exercised in handling to prevent wilting.
(Quoted from USDA Ag. Handbook #66):
Mature topped carrots can be stored 7 to 9 months at 32 to 34°F. with a very high relative humidity, 98 to 100%. However, even under these optimum conditions 10 to 20% of the carrots may show some decay after 7 months. Under commonly found commercial conditions (32 to 40°F.) with 90 to 95% relative humidity, 5 to 6 months’ storage is a more realistic expectation. Prompt cooling to 40°F or below after harvest is essential for extended storage. Poorly pre-cooled roots decay more rapidly.
Store carrots at 32°F and relative humidity of 98 to 100%. Mature carrots are well adapted for storage and are stored in large quantities during the fall and winter for both the fresh market and processing. Careful handling during and after harvest to avoid bruising, cutting and breakage will help ensure successful storage. Carrots held at or below 30°F will freeze. Ice crystals will form, giving the roots a bristly appearance and cracks. Severe injury in carrots immediately after freezing is identified by lengthwise cracking and by blistering caused by the formation of ice crystals immediately beneath the surface. After thawing, a darkened and water-soaked skin is observed, and the carrots are soft and flabby.
The most important decays of carrots in storage are grey mold rot (Botrytis), watery soft rot (Sclerotinia), crater rot (Rhizoctonia), Fusarium rot, Rhizopus soft rot, bacterial soft rot, black rot (Stemphylium), and sour rot (Geotrichum). Spoilage losses will be minimized if the following precautions are observed: Use new or disinfected storage containers, handle carefully to prevent injuries, pre-cool carrots, maintain them at a temperature near 32°F and avoid temperature fluctuations.
Carrots lose moisture readily and wilting results. Humidity should be kept high. Carrots stored at 98 to 100% relative humidity develop less decay, lose less moisture, and remain crisper than those stored at 90 to 95% relative humidity. A temperature of 31 to 34°F. is essential if decay and sprouting are to be minimized. With storage at 40 to 50°F, considerable decay and sprouting may develop within 1 to 3 months.
Pre-storage washing of carrots in clean water containing 100 ppm chlorine is desirable. Many potential decay-causing organisms are removed by washing. Also, clean, washed carrots allow freer air circulation. Air circulation within bulk piles of stored carrots is desirable to remove respiratory heat, maintain uniform temperatures, and help prevent condensation. An air velocity of about 14 to 20 ft/min is adequate at low storage temperatures.
Immature bunched carrot storage life is limited by the high perishability of the tops. They should keep 2 weeks at 32°F with 95 to 100% relative humidity. Contact ice is recommended to maintain freshness.
Packaging
Immature or partially mature carrots should be topped and packed in polyethylene consumer bags or 50 lb. mesh bags for marketing. Most carrots for the fresh market are of this type. If pre-cooled promptly before packaging and trimmed of all traces of leaf growth, they can be held 4 to 6 weeks at 32°F with 98 to 100% relative humidity recommended. Film bags for carrots should be perforated to allow ventilation and prevent development of off-odors or off-flavours. Six 1/8th inch holes of 1 lb. bags are suggested for ventilation.
Immature, topped carrots may be hydro-cooled or packed in crushed ice for cooling. Loose carrots can be hydro-cooled from 75 to 40°F in about 9 minutes if the water is 33°F. If the carrots are in 50 lb. mesh bags, the same degree of cooling requires about 11 minutes. Sometimes top ice is used with bagged, pre-cooled carrots. The top ice provides some of the necessary refrigeration and prevents dehydration.
Bitterness in carrots, which may develop in storage, is due to abnormal metabolism caused by ethylene. This gas is given off by apples, pears, and certain other fruits and vegetables and from decaying tissues. Bitterness can be prevented by storing carrots away from such produce. Also, development of bitterness can largely be avoided by low-temperature storage, as it minimizes ethylene production. Some surface browning or oxidative discoloration often develops in stored carrots. The most immature carrots are the most susceptible to surface browning.
Product description
Carrots belong to the Umbelliferon family and are thought to be of Asian origin.
Carrots, which are root vegetables, are divided into greenhouse and early carrots, summer and autumn carrots and late and keeping carrots.
Greenhouse and early carrots have a short root, which is usually blunt at the lower end, while later varieties have a long-pointed root. They are orange-red in colour and consist of the central medulla and the outer cortex. Their colour is provided by their high carotene content (carrots have the highest carotene content of all vegetable species). Since the medulla has a lower carotene and sugar content than the cortex, it is somewhat lighter in colour and of lower nutritional value. For this reason, carrots with a thick cortex and a small, well-coloured medulla are preferred. The relatively high sugar content gives carrots a delicate flavour.
The green foliage grows at the upper end of the root, and, in the case of early carrots (bunch carrots), is not removed. However, later varieties are sold washed without their foliage.
Quality / Duration of storage
Carrots must be free from mechanical damage and insects and of uniform color (the upper part of the root should not be green) and shape. They must not be bitter to taste or woody in texture.
Various sources state maximum duration of storage as follows:
| Temperature | Rel. humidity | Max. duration of storage |
| 0.5 – 2°C | 95% | 28 days |
| 0 – 1°C | 95% | 21 – 28 days |
| 0 – 1°C | not stated | 10 days |
The storage and transport duration of carrots cannot be markedly extended by using controlled atmosphere transport. It merely reduces the risk of the carrots becoming bitter due to the ripening gas ethylene.
Intended use
Carrots may be eaten raw or cooked with various dishes and are also used in the preparation of salads, stews and carrot juice and for canning.
Means of transport
Ship, truck, railroad, aircraft
Container transport
Refrigerated container with fresh air supply
Cargo handling
Since carrots are sensitive to impact, they must be handled with appropriate care. The required refrigeration temperature must always be maintained, even during cargo handling.
In damp weather (rain, snow), the cargo must be protected from moisture, as there is otherwise a risk of premature spoilage.
Storage factor
- 40 m3/t (fruit crates)
- 12 – 2.27 m3/t (crates)
- 84 – 1.98 m3/t (boxes and bags)
Storage space requirements
Cool, dry, well ventilated
http://www.tis-gdv.de/tis_e/ware/gemuese/moehren/moehren.htm
Storage Diseases
Major post-harvest losses in carrots are due to Sclerotinia rot, Botrytis rot, Bacterial soft rot (Erwinia) and Sour rot (Geotrichum). Of these, Sclerotinia rot is the most prevalent. The Sclerotinia fungus infects the carrot roots in the field through the crown. During storage, the Sclerotinia fungus produces a white, cottony mycelium which covers the roots. Infected roots are usually soft and watery. Storage losses to Sclerotinia can be minimized by:
- pre-harvest application of a registered fungicide such as Bravo 500
- rapid removal of field heat from freshly harvested roots
- increasing row width to increase ventilation since prolonged periods of leaf wetness induce rot
- crop rotation
- post-harvest application of a registered antimicrobial such as Dowicide (Ophenylphenol) at a concentration of 98 g/L.
http://www.agr.gc.ca/resources/prod/doc/pfra-arap/csidc-crdi/pdf/carrots-carottes_eng.pdf
Market Structure
There is no regulation or restriction in the marketing of carrots. The prices of carrots are determined by market forces of demand and supply. The industry uses local market, informal market, processor and direct selling to wholesalers and retailers. Carrots are also exported to other countries through export agents and marketing companies. South Africa also imports carrots from other countries.
Exports
South Africa is not a major carrot exporter, it represents 0.25% of world exports and its ranked number 27 in the world. Most of carrots produced were destined for domestic markets. South Africa carrots exports were mostly destined to United Kingdom, France, Angola, Mozambique, Mauritius, Netherlands and Switzerland. Globally China, Netherlands, USA, Italy, Spain, Belgium, France, Canada, Australia are major carrot exporters. Figure 5 below, illustrates South African carrot export destination.
General Distribution Channels
There are roughly three distinct sales channels for exporting vegetables. One can sell directly to an importer with or without the assistance of an agent (usually larger, more established commercial farms/orchards). One can supply a vegetable combine, which will then contract out importers/marketers and try to take advantage of economies of scale and increased bargaining power. At the same time vegetable combines might also supply large retail chains. One can also be a member of a private or co-operate export organization (including marketing boards) which will find agents or importers and market the produce collectively. Similar to a vegetable combine, an export organization can either supply wholesale markets or retail chains depending on particular circumstances. Export organizations and marketing boards will wash, sort and package the produce.
Logistical Issues
Mode of transport
The transportation of vegetables falls within two categories – ocean cargo and air cargo – with ocean cargo taking much longer to reach the desired location but costing considerably less. Of course, the choice of transportation method depends, for the most part, on the fragility of the produce and how long it can remain relatively fresh. With the advent of technology and container improvements, the feasibility, cost and attractiveness of sea transportation have improved considerably. As more developing countries begin to export and supply major developed countries markets, so the number and regularity of maritime routes, and the container vessels travelling these routes, increase. Presently South American countries like Peru benefit from the asparagus trade, which has led to some level of economies of scale with other vegetable products, and this has enabled cheaper transport prices for their other vegetable varieties. Such economic of scale could benefit SADC countries if more producers became exporters and took advantage of the various ports which have special capabilities in handling vegetable produce (for example, the proposed terminal in Maputo). For some products, in order to reach the destination market with an acceptable degree of freshness, air transport is the only option (asparagus, for example, is flown from Peru to the sufficient to cover the transport costs, and collective agreements between farmers of different commodities with different harvest periods can become particularly important.
Cold chain management is crucial when handling perishable products, from the initial packing houses to the refrigerated container trucks that transport the produce to the shipping terminals, through to the storage facilities at these terminals (and their pre-cooling capability), onto the actual shipping vessels and their containers, and finally on to the importers and distributors that must clear the produce and transport it to the markets/retail outlets, etc. For every 10oC increase above the recommended temperature, the rate of respiration and ripening of produce can increase twice or even thrice. Related to this are the increasingly important traceability standards, which require an efficiently controlled supply chain and internationally accepted business standards. 5.3 Packaging also plays a vital role in ensuring safe and efficient transport of a product and conforming to handling requirements, uniformity, recyclable materials specifications, phytosanitary requirements, proper storage needs and even attractiveness (for marketing purposes).
Opportunities and Challenges
Opportunities
Carrots have found increasing favour among consumers. Several health benefits have promoted marketing this vegetable as a convenient and good tasting snack food or juice product. Carrots are popular as snacks, side dishes, salads ingredients, juice mixtures and dessert mixtures (e.g. carrot cake and carrot pudding). The rise of the fresh cut industry has meant some of the misshapen and other wise imperfect carrots have an alternative profitable outlet. Carrot that would not have made the grade in a standard pack of fresh carrots do not have to be sent to freezers or canners to be cut, diced or juiced. Today, the cutting and peeling process for various fresh-cut carrot products allows a majority of the raw carrots destined for the fresh market to become fresh market products.
Challenges
The major concern is the production of a disease-free high quality clean carrot root. Other essential part of carrot production and marketing is the need to define the quality standards necessary for consumer acceptance. Product physical defects can be readily measured, but the flavour and sweetness characteristics must be defined and the parameters affecting these important factors understood. Numerous root diseases affect carrot but proper cultural practices can keep them under control. Carrot growers also face strong market competition from the national and international producers. http://www.nda.agric.za/docs/AMCP/CarrotVCP2009-2010.pdf
Washing, peeling and sorting
Carrots are fed to the plant in cases, bins, bags or in bulk. A comprehensive washing is essential, as large quantities of mud and stones may be transported together with the product.
Receiving at the plant
After being washed, carrots are peeled by steam (tall machine on the right) and then brushed (two machines in series)
Sorting line. This carrot processing plant is located in China and it’s able to process up to 10 tons of carrots per hour.
Chopping and cooking
The washed and peeled carrots are chopped before going to the treatment line. The chopping dimensions depend on the required extraction (puree or pressed juice). The chopped carrots are heated in a tubular cooker to soften the fibers and to get consequently the maximum juice yield.
Chopper
Tubular cooker
Carrot juice: extraction
Belt press allows to recover up to 75% of juice with a single pressing or more than 85% with a double pressing.
Belt press
The waste of the belt press
Carrot juice coming from the press
Plate centrifuge
Carrot juice: concetration
Optionally, juice can be concentrated. Our plate evaporator model Flesh term is particularly suitable for the production of concentrated carrot juices up to the Brix values required by the market.
Two effects plate evaporator Flashterm
Carrot puree: refining
We offer different machines for the refining of carrot purees. Depending on the requirements the process can take place either in one or two stages.
Two Turbomax pulpers
Sterilization and aseptic filling
Sterilflash is a plate sterilizer suitable for the treatment of carrot juice concentrated at 40°Brix. For carrot puree
Bertuzzi provides its lines with tubular sterilizers, and possibly with a dearator, to increase product shelf-life.
Sterilflash plate sterilizer is the best choice for low viscosity juices
Tube-in-tube sterilizer
